This invention relates to new boron resins possessing very high selective absorbent power which are stable in organic solvents and in aqueous acid and alkaline solutions.
More particularly, the invention relates to boron resins consisting of an acrylic polymer matrix functionalized with quaternary ammonium groups, an epoxy group and phenylboric groups of general formula (I): ##STR2## in which:
P is a polyacrylic matrix,
R is --(CH.sub.2).sub.n -- where n lies between 0 and 5,
R.sub.1 and R.sub.2, which can be the same or different, are C.sub.1 -C.sub.5 alkyl,
R.sub.3 is --(CH.sub.2).sub.n -- where n varies from 1 to 5,
Y is --O--, --S--, ##STR3## where R is a C.sub.1 -C.sub.5 alkyl, and
X.sup.- is an anion chosen from halogens and hydroxyl;
The invention also relates to a process for producing the boron resins defined by general formula (I).
In European Patent 8510934.8 we have already described boron resins with a polyacrylic matrix bifunctionalized with quaternary ammonium groups and alkylphenylboric groups, which possess good chemical and mechanical stability characteristics and can be used in industrial processes, they having a marked selective absorbent action particularly in separating lactulose from its mixtures with other carbohydrates, generally lactose and galactose.
It has now been discovered that boron resins with further improved selectivity in separating sugars can be obtained by the process of the present invention, which is described in detail hereinafter.